What does the Low-Pass filter do (for dummies)

Dear colleagues,
I'm about to encode a lot of content for DVD using Apple Compressor Vers 3.5.2. This project calls for 2.0 Stereo as well as 5.1 surround. I am wondering if I should check or un-check the Low-Pass Filter for the Full Bandwidth Channels for the 2.0 stereo track.
Same question for the 5.1...
In case it's important to note, the LFE track of the 5.1 mix has low frequency effects only and nothing else.
The explanation in the manual seems confusing to me. Would someone be kind enough to help me determine the correct setting?
Thanks in advance!
Xavier

Hi David,
Thanks for your reply. I think I'll just turn OFF this filter for both my 2.0 Stereo and 5.1 Surround tracks.
In the name of proper communication however something still doesn't make sense. The compressor manual states the following:
Full Bandwidth Channels
Apply Low-Pass Filter: Select this checkbox to turn on a low-pass filter with a cutoff near the available audio bandwidth that is applied to the main input channels. If the digital signal fed to the main input channels does not contain information above the available audio bandwidth, you can turn off this filter. Compressor will automatically determine the available bandwidth.
Question 1: What/which is the available audio bandwidth?
Question 2: Why would anyone want to apply a Low-Pass filter to a FULL bandwidth channel? I would think that since these are FULL bandwidth channels you would want to maintain the full range of frequencies. No?

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could you maybe provide us with a more specific example? What kinds of filters have you tried?
For information on advanced digital filter use, please see the following pages:
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Maybe you could look into trying the NI LabVIEW Digital Filter Design Toolkit
Happy holidays!
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What does the Low-Pass filter do (for dummies)

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